Maintaining a relatively uniform temperature is important in any refrigeration system, but it is particularly important in the context of food and beverage refrigeration. Without proper temperature distribution, some food in a refrigerator will be too cold, resulting in unwanted freezing and some will be too warm, which raises the risk of spoilage. In most contexts, a uniform temperature is not only desirable, but is mandated by regulations. For example, depending upon the aircraft operating authority certain types of food served on passenger airlines is required to be maintained at a maximum temperature of no more than 7° C. and in some countries 4° C.
Typically, pre-prepared airline food is stored in galley carts prior to serving to passengers. However, current galley cooling systems have to force air just above freezing either into the galley carts or into insulated compartments containing several galley carts just to ensure that the temperature does not exceed the required temperature in any portion of the carts. This is due to the temperature increase as the air passes through or over the galley carts to remove the heat entering the galley cart or compartment. The lower maximum temperature requirement of 4° C. means that the current cold air source is less efficient resulting in the need to use more powerful and heavier systems that use more electrical power. Thus, it can be seen that there is a need for a new method and apparatus for maintaining a uniform temperature in a refrigeration system.